Université Montpellier 2, Laboratoire Charles Coulomb UMR 5221, F-34095, Montpellier, France.
Sci Rep. 2013;3:2355. doi: 10.1038/srep02355.
The ultimate surface exposure provided by graphene monolayer makes it the ideal sensor platform but also exposes its intrinsic properties to any environmental perturbations. In this work, we demonstrate that the charge carrier density of graphene exfoliated on a SiO2/Si substrate can be finely and reversibly tuned between hole and electron doping with visible photons. This photo-induced doping happens under moderate laser power conditions but is significantly affected by the substrate cleaning method. In particular, it requires hydrophilic substrates and vanishes for suspended graphene. These findings suggest that optically gated graphene devices operating with a sub-second time scale can be envisioned and that Raman spectroscopy is not always as non-invasive as generally assumed.
单层石墨烯具有极高的表面暴露程度，这使其成为理想的传感器平台，但同时也使它的固有性质容易受到任何环境干扰。在这项工作中，我们证明了在 SiO2/Si 衬底上剥离的石墨烯的载流子密度可以通过可见光光子在空穴掺杂和电子掺杂之间进行精细和可逆地调节。这种光致掺杂发生在中等激光功率条件下，但显著受到衬底清洁方法的影响。具体而言，它需要亲水衬底，对于悬空的石墨烯则会消失。这些发现表明，可以设想使用亚秒级时间尺度进行光控栅极石墨烯器件的操作，并且拉曼光谱并不总是像通常假设的那样具有非侵入性。
